The Chemical Dynamics and Spectroscopy Group consists of seven research fellows and three adjunct fellows. The research objectives of this group are to provide a better understanding of (1) the structure and chemical behavior of highly reactive polyatomic radicals and unusual transient species, (2) the microscopic details of the mechanisms and dynamics of elementary chemical reactions and primary photodissociation processes, and (3) the nature of intra- and inter-molecular energy transfer.
The group has four state-of-the-art crossed molecular beam machines. The first two, designed and managed by Y. T. Lee and J. J. Lin, employ the electron-impact-ionization/mass spectrometry detection scheme, and are ideal for studying complex chemical reactions with multiple product channels. Lee and Lin have a close collaboration with the National Synchrotron Radiation Research Center on the Chemical Dynamics end-station. Here they use the photoionization (i.e., a ¡§soft¡¨ ionization) detection scheme for studies of chemical reaction dynamics. A rotating-sources machine, envisioned by K. Liu, employs laser spectroscopy and a time-sliced velocity imaging technique to elucidate the state-to-state reactivity of elementary chemical reactions. The fourth machine, built and managed by C. K. Ni, also employs the ion velocity imaging technique, and is aimed at investigating the molecular energy transfer processes of highly vibrationally excited species. Y. T. Lee and C. K. Ni have also constructed a unique multi-mass ion imaging machine that allows simultaneous measurement of translational energy distributions of many different fragments from the photodissociation of numerous organic molecules.
Y.-C. Hsu and H.-T. Liou focus on high-resolution spectroscopic studies of transient radicals and highly vibrationally excited species, respectively. Various optical spectroscopic techniques, such as laser-induced fluorescence, double- or triple-resonance, stimulated emission pumping, and dispersed fluorescence are used to provide structural and dynamical information of these exotic species.
The research activities of three adjunct members, Y.-P. Lee, K.-C. Lin, and Y.-T.
Chen, complement the efforts of this group. The main thrusts of Y.-P. Lee's research lie in matrix-isolation spectroscopy and photo-fragmentation studies by step-scan time-resolved Fourier-transform spectroscopy. K.-C. Lin
works on the kinetics and dynamics of small
molecules. |
